This is an application for funds to conduct and publish the transactions of the Twelfth Princeton Conference on Cerebrovascular Disease to be held March 2, 3, 4, 1980. Since the first conference held in 1954 this meeting and the publication of its proceedings have generated widespread interest among investigators developing and applying new information about cerebrovascular disease. A broad spectrum of institutions, scientific and clinical disciplines and geographic areas has been represented over the years at this conference which has thereby served as a forum for exchanging ideas and for stimulating new studies of human and experimental cerebrovascular disease.